Fuel Injected Engines

Refer to Fuel Injection Section to access self-diagnosis codes. If self-diagnosis code 12 is stored in ECU check appropriate vacuum tubes for loose connections.
1. Start engine and allow to reach normal operating temperature.
2. Disconnect vacuum hose from top of EGR valve, then connect a suitable hand vacuum pump to the EGR valve.
3. Measure vacuum at idle with lower hose of the EGR solenoid valve in number 2 control box pinched.
4. If vacuum stabilizes at 5.9-9.8 inches Hg, CVC valve is satisfactory. If vacuum is not 5.9-9.8 inches Hg, check hose between intake manifold and vacuum gauge for clogging, kinking or leakage. If hose is satisfactory, replace CVC valve.
5. Unclamp hose pinched in step 3, then note vacuum.
6. If vacuum is below 1.2 inches Hg, EGR control solenoid valve is satisfactory. If vacuum is greater than 1.2 inches Hg, check air flow hose to the EGR control solenoid valve for blockage. If hose is satisfactory, replace EGR control solenoid valve.
7. Stop engine, reconnect vacuum hose to EGR valve and disconnect vacuum hose number 21 between throttle body and intake air pressure sensor.
8. Plug vacuum opening at throttle body, then connect a suitable hand vacuum pump to vacuum hose number 21. Apply 11.8 inches Hg of vacuum.
9. Raise engine speed to 2400 RPM and feel operation of EGR control solenoid valve with your fingers.
10. If EGR control solenoid valve is operating, system is satisfactory. If EGR control solenoid valve is not operating, check harness between EGR control solenoid valve and ECU for opens or short circuits.
11. If harness is satisfactory, check EGR control solenoid valve for proper operation. If EGR control solenoid valve is satisfactory, check EGR valve and lift sensor for proper operation.